advice? evaporator coil replacement work

Originally Posted By: Jerome Ball
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I’d appreciate any feedback on the following quotes I’ve received on replacing a leaking 4-ton evap coil with a new coil from American Standard. The HVAC quote is looking for $1400 to replace the coil (and drain pan and recharge, etc.). My web browsing indicates this might be rather high, but I’m unclear whether the ASD coil is indeed significantly better (a claim I saw somewhere).

The replacement coil would be 4 1/2 ton - I'm looking to upgrade the condenser eventually from 4 to 5 ton as we've had longstanding issues keeping the upstairs cool.

Is $1400 reasonable for this job (possibly just for a 4-ton, not 4 1/2)?

Second, they are looking for $3200 to: A) replace the coil, B) modify/add supplies and returns in 4 rooms upstairs to improve cooling even without going to a larger condenser/evaporator set, and C) eliminate several "branching boxes" used in the original ducting system in the attic because these reduce airflow/cooling efficiency. Right now, there is at least one and maybe two? stages of duct branching between the evaporator and the return to a given room.

Questions are: Is C) a valid concern? Is duct branching inherently evil? Is B) likely to help with our upstairs cooling even without going to a larger system? Finally, is $3200 reasonable for all this.

Finally, what they'd really like me to buy is $11,000 worth of state-of-the-art new 19seer 5-ton Trane, furnace, evaporator, running the new line set needed for this, and improved ducting. My pocketbook isn't quite that thick regardless of whether the price is reasonable ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif), but I'd appreciate comments on it anyway.

The house is large (6400 sq ft, four zones) and in the past I've found the company reasonably-priced on maintenance visits, use good people, and do quality work.

But am I paying too high a "nice neighborhood" premium? My kids are presently sleeping downstairs, awaiting your replies... ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

Thanks for wading through all this.

Originally Posted By: jsavino
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What part of the country are you in?

Seeing that it’s mid August, and if you are located in the northern parts of the country, c/a/c season is about finished, I would do the repairs in stages. Maybe replace the coil now, and other repairs over the winter months when a/c companies are not as busy.

$11,000 for what you described is reasonable. Get other estimates, if you are in doubt, of the work and equipment. Just make sure you are all talking apples not apples and oranges, if you know what I mean.

But if you like their work and have found to be reasonable priced, reliable, and responsive to your needs, then you pay the freight.

John Savino

HomeWorks Inspection Services, LLC

St. James, NY


Originally Posted By: Guest
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For God’s sake you have a 6,400 square foot house. Just cough up the cash.

Originally Posted By: dedwards
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Mr. Ball,

First thing I would do is get several more bids. Never go with just one and assume that is the best you can do. It is difficult for any of us to tell you that is a good price without “seeing” the extent of work and/or repairs and remodeling of your existing system needs. With HVAC there are dozens of variables that come into play. One giant AC for a house this big is usually not a very effective way to go. Just the placement of the single thermostat will have a significant effect on the way the system performs. You could do all of that and still have a heat problem upstairs. Why? Because hot air naturally rises to the second floor and accumulates upstairs. Meanwhile cold air is heavier and sinks to the lower half of the rooms downstairs. If the thermostat is downstairs it will naturally sense the cool temperatures in it’s surroundings and not call for cooling. Meanwhile it continues to stay hot upstairs. The ductwork can very much have an effect on the way the system performs. Most of the AC I look at (I have a HVAC certification) the ductwork is one of the weakest components. Either through poorly designed, and sloppy connections at the ductwork collars and believe it or not “duct tape”. Duct tape (the gray crap you can buy at Walmart is not made for HVAC ductwork). Back to the original question. You may want to get a few more quotes and contact some of the home inspectors in your area to see who they may recommend. We get to see their handiwork up close almost daily. Some do great work, some do not so great. Hope this helps.

Originally Posted By: psabados
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I don’t know guys

Lots of things to consider. 6400 sf on multiple levels, add in the possiblity of high ceilings and stairwells. That's a lot of cubic feet that needs to be conditioned. One single unit even a 5 tons seems to be stretching it and can you even get enough volume (cfrm) from one unit

Twin 3-ton or even a combo of 4/3 would appear to be the wise way to go. A lot better zone control and less energy waste. Yes its expensive, but probably should have been designed that way. It just seems like way to much area, that A/C will never shut down during a hot spell.


Originally Posted By: dedwards
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Agree. Only I think a big single unit will be constantly short cycling. The downstairs would very quickly hit the temperature selected on the thermostat but not run long enough to cool any of the upstairs. Even a packaged terminal heat pump added for the upstairs would be an improvement over one oversized unit trying to cool a home that big. I agree too about the zone controls. Almost all new houses here in the panhandle of Florida, if it is two story, will have two smaller units independent of each other on separate thermostats. One upstairs and one downstairs. Twice as much equipment but a lot more efficient than one monolith AC on the side of the house.

Originally Posted By: Jerome Ball
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Thanks for all the responses. For the sake of clarity, the house is in the Dallas area and I heartily concur a single 4-ton wouldn’t cut it. icon_wink.gif The house has a 5-ton unit and three additional 4-ton units splitting the house into 4 zones total. So I could afford the time to shop around with 3 out of 4 units keeping us alive;)

For anyone else in the market for a coil, my "low end" bid, from a couple of professional HVAC guys moonlighting, was at $1200 for the coil replacement and about $1200 for major re-ducting work for the single unit. They concurred that the break-out boxes I had were bad news. Also mentioned that the new plenum box should be insulated on the outside, not the inside (apparently that's a shortcut some builders take to assemble the plenum separately and minimize attic time).

Unfortunately, the "moonlighters" are working so much summer overtime that I'll have to go with the regular HVAC company; $3200 is expensive but probably not completely out of whack considering it includes company overhead.